Responses of radiata pine clones to varying levels of pasture competition in a semiarid environment

1999 ◽  
Vol 29 (7) ◽  
pp. 934-939 ◽  
Author(s):  
E G Mason ◽  
B Kirongo
Keyword(s):  
New Zealand ◽  
Coefficient Of Variation ◽  
Genetic Effect ◽  
Radiata Pine ◽  
Competitive Environment ◽  
First Year ◽  
Weed Competition ◽  
Variable Response ◽  
Semiarid Environment ◽  
Four Levels

An experiment comprising seven clones with four levels of weed competition was established on a semiarid site on the Canterbury plains, New Zealand, during September 1996. Previous experiments showed that trees subjected to little competition from weeds did not always respond to their favourable environments, resulting in more variation among individuals subjected to less competition. The aim of this experiment was to determine whether the variable response to competitive environment is partly a genetic effect. The main plots consisted of four levels of competition: no competition and cleared spots: 3.14, 0.75, and 0.03 m2. Within each plot there were 10 individuals of each clone. Trees generally grew more rapidly with increasing amounts of clear ground, but increasing spots beyond 3.14 m2 did not increase growth during the first year. Variation, expressed as coefficient of variation, was greater among trees subjected to more competition. Within clone coefficient of variation was not related to level of competition.

Interactions between influences of genotype and grass competition on growth and wood stiffness of juvenile radiata pine in a summer-dry environment

2006 ◽  
Vol 36 (10) ◽  
pp. 2454-2463 ◽  
Author(s):  
Euan G Mason
Keyword(s):  
New Zealand ◽  
Pinus Radiata ◽  
Dynamic Modulus ◽  
Radiata Pine ◽  
Spot Size ◽  
The Other ◽  
First Year ◽  
Wood Stiffness ◽  
Experiment Control ◽  
Four Levels

Clones of radiata pine (Pinus radiata D. Don) were established in two experiments on two contrasting pasture sites in Canterbury, New Zealand, with four levels of competition from grass as main plots within each experiment. Control was extended over the first 5 years at one site, whereas grass at the other site was controlled by a single herbicidal spray immediately after planting. At the latter site, 1 m diameter spots cleared with herbicide were compared with the same size spot created using a woven mat. Grass competition added up to 3 years to a rotation, and the gain from control was correlated with spot size. Competition control was most critical during the first year after planting. Trees grown within spots cleared by mats grew more slowly than those in weed-free spots cleared with herbicide. Green dynamic modulus of elasticity was related to genotype and increased with both slenderness and higher levels of pruning. Significant interactions between genotype and level of competition were observed for growth, indicating that choice of genotype can be a useful way of coping with pasture competition if managers wish to reduce the use of herbicides.

scholarly journals Modelling variation in wood density within and among trees in stands of New Zealand-grown radiata pine

2015 ◽  
Vol 45 (1) ◽  
Author(s):  
Mark O. Kimberley ◽  
Dave J. Cown ◽  
Russell B. McKinley ◽  
John R. Moore ◽  
Leslie J. Dowling
Keyword(s):  
New Zealand ◽  
Wood Density ◽  
Radiata Pine

Responses to supplements by weaned lambs when grazing mature pasture or eating hay cut from the same pasture

1988 ◽  
Vol 110 (3) ◽  
pp. 661-667 ◽  
Author(s):  
M. Freer ◽  
H. Dove ◽  
A. Axelsen ◽  
J. R. Donnelly
Keyword(s):  
Weight Gain ◽  
Coefficient Of Variation ◽  
Substitution Rate ◽  
Eating Behaviour ◽  
Sunflower Meal ◽  
Total Intake ◽  
Grazed Pasture ◽  
Ad Libitum ◽  
Four Levels ◽  
Supplement Intake

SummaryWeaned cross-bred lambs either grazed mature pasture or were confined to yards where they were offered material cut from ungrazed areas of the same pasture. A 1:2 mixture (on an air-dry basis) of sunflower meal and oat grain was offered for 81 days at 0, 200, 400 or 600 g/head or ad libitum. Individual estimates of intake of pasture and supplement by grazing sheep at four levels of supplementation were made on four adjacent plots.Weight gain increased from –30 to 178 g/day in the grazing animals as supplement intake increased up to 1030 g D.M./day and from –25 to 142 g/day in the yarded animals as supplement intake increased to 1076 g D.M./day. Growth of greasy wool increased from 4·5 to 11·7 g/day for grazing animals and from 4·5 to 10·2 g/day for those kept in yards.At levels of supplement intake below 400 g D.M./day, the intake of grazed pasture increased by up to 58% compared with unsupplemented animals. However, when the intake of supplement was increased to about 650 g D.M./day, pasture intake fell, with an estimated substitution rate of 1·1 g D.M. pasture per g D.M. supplement. At all levels of supplementation, the intake of hay by the yarded lambs was less than half the intake of herbage in the field. However, at levels of supplement intake between 300 and 500 g D.M./day, the substitution rate was similar to that measured in the grazing animals, suggesting that this is an attribute of roughage quality, rather than differential eating behaviour between grazing and yarded animals.The wastage, w (g D.M./day), of supplement was linearly related to the amount offered, s (g D.M./day), by the equationw = 0·263s − 38·8; R2 = 0·89Variability in supplement intake between individual grazing lambs was not affected by the level of supplementation but the coefficient of variation of supplement intake was considerably greater than that of the intake of unsupplemented pasture. Variability in the intake of pasture increased with the level of supplementation but variability in the total intake of food was similar at each level of supplement, indicating some degree of individual compensation in the intake of the two components.

scholarly journals Saints and Sinners: Arthur Espie Porritt

2013 ◽  
Vol 95 (8) ◽  
pp. 274-275
Author(s):  
Wyn Beasley
Keyword(s):  
New Zealand ◽  
Royal College ◽  
First World War ◽  
First Year ◽  
World War ◽  
The First World War ◽  
The Future ◽  
First World

Arthur Porritt, whose adventures, accolades and achievements spanned the globe, was both a surgeon himself and the son of a surgeon. His father, Ernest Edward Porritt, qualified in Edinburgh, became a fellow of the Royal College of Surgeons of Edinburgh in 1898, and practised in Wanganui in new zealand, where Arthur was born on 10 August 1900. His mother, Ivy McKenzie, died in 1914, when Arthur was in his first year at Wanganui Collegiate School; and when his father shortly went overseas to serve in the First World War, the boy became a boarder. The future Olympian distinguished himself as athletics champion, a member of the First XV and a prefect; and for a year after leaving school himself, he taught at a boys' school.

scholarly journals Estimates of (co)variance components and genetic parameters for body weights and growth efficiency traits in the New Zealand white rabbit

2017 ◽  
Vol 25 (4) ◽  
pp. 329 ◽  
Author(s):  
M. Sakthivel ◽  
D. Balasubramanyam ◽  
P. Kumarasamy ◽  
H. Gopi ◽  
A. Raja ◽  
...  
Keyword(s):  
Body Weight ◽  
New Zealand ◽  
Variance Components ◽  
Environmental Effect ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Effect ◽  
Growth Efficiency ◽  
Body Weights ◽  
Heritability Estimates

The genetic parameters of growth traits in the New Zealand White rabbits kept at Sheep Breeding and Research Station, Sandynallah, The Nilgiris, India were estimated by partitioning the variance and covariance components. The (co)variance components of body weights at weaning (W42), post-weaning (W70) and marketing (W135) age and growth efficiency traits viz., average daily gain (ADG), relative growth rate (RGR) and Kleiber ratio (KR) estimated on a daily basis at different age intervals (42 to 70 d; 70 to 135 d and 42 to 135 d) from weaning to marketing were estimated by restricted maximum likelihood, fitting 6 animal models with various combinations of direct and maternal effects. Data were collected over a period of 15 yr (1998 to 2012). A log-likelihood ratio test was used to select the most appropriate univariate model for each trait, which was subsequently used in bivariate analysis. Heritability estimates for W42, W70 and W135 were 0.42±0.07, 0.40±0.08 and 0.27±0.07, respectively. Heritability estimates of growth efficiency traits were moderate to high (0.18 to 0.42). Of the total phenotypic variation, maternal genetic effect contributed 14 to 32% for early body weight traits (W42 and W70) and ADG1. The contribution of maternal permanent environmental effect varied from 6 to 18% for W42 and for all the growth efficiency traits except for KR2. Maternal permanent environmental effect on most of the growth efficiency traits was a carryover effect of maternal care during weaning. Direct maternal genetic correlations, for the traits in which maternal genetic effect was significant, were moderate to high in magnitude and negative in direction. Maternal effect declined as the age of the animal increased. The estimates of total heritability and maternal across year repeatability for growth traits were moderate and an optimum rate of genetic progress seems possible in the herd by mass selection. The genetic and phenotypic correlations among body weights and between growth efficiency traits were also estimated. Moderate to high heritability and higher genetic correlation in body weight traits promise good scope for genetic improvement provided measures are taken to keep the inbreeding at the lowest level.

scholarly journals Mother and Infant Nutrition Investigation in New Zealand (MINI Project): Protocol for an Observational Longitudinal Cohort Study

10.2196/18560 ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. e18560
Author(s):  
Ying Jin ◽  
Jane Coad ◽  
Shao J Zhou ◽  
Sheila Skeaff ◽  
Cheryl Benn ◽  
...  
Keyword(s):  
Cohort Study ◽  
New Zealand ◽  
Thyroid Function ◽  
Postnatal Depression ◽  
Infant Nutrition ◽  
Trial Registration ◽  
Longitudinal Cohort Study ◽  
First Year ◽  
Selenium Status ◽  
Iodine Status

Background Thyroid dysfunction is associated with cognitive impairment, mood disturbance, and postnatal depression. Sufficient thyroid hormone synthesis requires adequate intake of iodine, selenium, and iron. Iodine deficiency was historically a problem for New Zealand, and initiatives were introduced to overcome the problem: (1) mandatory fortification of all bread (except organic) with iodized salt (2009) and (2) provision of subsidized iodine supplements for pregnant and breastfeeding women (2010). Subsequent to these initiatives, most adults and children have adequate iodine status; however, status among breastfeeding women and their infants remains unclear. This paper outlines the methodology of the Mother and Infant Nutrition Investigation (MINI) study: an observational longitudinal cohort study of breastfeeding women and their infants. Objective This study will determine (1) women’s iodine intake and status among supplement users and nonusers; (2) women’s intake and status of iodine, selenium, and iron relating to thyroid function; (3) associations between women’s selenium status, thyroid function, and postnatal depression; (4) infants’ iodine and selenium status relating to first year neurodevelopment. Methods Breastfeeding women aged over 16 years with a healthy term singleton infant were recruited from Manawatu, New Zealand. Participants attended study visits 3, 6, and 12 months postpartum. Maternal questionnaires investigated supplement use before and after birth, iodine knowledge, and demographic information. Dietary assessment and urine, blood, and breast milk samples were taken to measure iodine, selenium, and iron intake/status. The Edinburgh Postnatal Depression Scale was used repeatedly to screen for postnatal depression. Thyroid hormones (free triiodothyronine, free thyroxine, thyroid stimulating hormone, thyroglobulin, antithyroglobulin antibodies, and antithyroid peroxidase) were measured in blood samples, and thyroid gland volume was measured by ultrasound at 6 months postpartum. Infant iodine and selenium concentrations were determined in urine. The Ages and Stages Questionnaire was used to assess infant development at 4, 8, and 12 months. Results Data collection was completed. Biological samples analysis, excluding nail clippings, is complete. Data analysis and presentation of the results will be available after 2020. Conclusions This study will provide data on the current iodine status of breastfeeding women. It will also provide a greater understanding of the three essential minerals required for optimal thyroid function among breastfeeding women. The prospective longitudinal design allows opportunities to examine women’s mental health and infant neurodevelopment throughout the first year, a crucial time for both mothers and their infants. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12615001028594; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=369324 International Registered Report Identifier (IRRID) DERR1-10.2196/18560

Calving dates and subsequent intercalving intervals in New Zealand beef herds

1984 ◽  
Vol 39 (1) ◽  
pp. 51-57 ◽  
Author(s):  
C. A. Morris
Keyword(s):  
New Zealand ◽  
First Year ◽  
Age Group ◽  
Regression Analyses ◽  
Industry Data ◽  
Beef Industry ◽  
Beef Herds ◽  
The Mean

ABSTRACTThe calving dates of spring-calving cows in New Zealand Angus and Hereford herds, taken from 350 and 240 herd-years respectively, and the intercalving intervals (CI) of cows in 95 Angus and 73 Hereford herds have been summarized. The relationships of each CI with the calving date which initiated it were also analysed. Results for each breed were analysed taking account of district, herd, year and cow age (in years), a total of 35 890 Angus and 22 397 Hereford records being used. The first-calving date (FCD) was identified for each herd-year, and 0·82 of Angus and 0·75 of Hereford cows were recorded as calving within 60 days of the FCD. On a herd basis, proportionately only 0·27 of Angus and 0·15 of Hereford herds had calving spreads of 80 days or less (defined as the time from the FCD to the last calving date). With barren years ignored, the CIs of cows averaged 370 days (Angus) and 368 days (Hereford). Two-year-old cows had on average a CI of 12 (Angus) or 7 days (Hereford) longer in 1974-75 than older cows, and the differences were both 12 days in 1975-76. Regression analyses showed that, on average, the later the calving date within a herd-year and age group, the shorter the subsequent CI. For cows calving early in the first year, the CI increased by 7 days for Angus and 5·4 days for Herefords for each 10 days before the mean calving date for the breed. There were significant effects of district and cow age on the regression estimates. The overall regressions were not consistent with those derived from British beef industry data.

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